Tudy of magnetic induction heating mechanisms of spinel ferrite nanoparticles M1 - Xznxfe2o4 (M = Mn, Co)

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADATE UNIVERSIY OF SCIENCE AND TECHNOLOGY  Pham Hong Nam STUDY OF MAGNETIC INDUCTION HEATING MECHANISMS OF SPINEL FERRITE NANOPARTICLES M1-xZnxFe2O4 (M = Mn, Co) Major: Electronic materials Code: 62.44.01.23 SUMMARY OF DOCTORAL THESIS IN MATERIAL SCIENCE Ha Noi - 2018 This thesis was done at: Laboratory of Biomedical Nanomaterials, Institute of Materials and Sciene, Vietnam Academy of Science and Technology. Supervisor: Assoc.Prof., Dr. Do Hung Manh Assoc.Prof., Dr. Pham Thanh Phong Reviewer 1: ..................................................... Reviewer 2: ..................................................... Reviewer 3: ..................................................... The dissertation will be defended at Graduate University of Science and Technology, 18 Hoang Quoc Viet street, Hanoi. Time: .............,.............., 2018 This thesis could be found at National Library of Vietnam, Library of Graduate University of Science and Technology, Library of Institute of Materials and Science, Library of Vietnam Academy of Science and Technology. 1 INTRODUCTION Currently, application of nanoparticle in magnetic hyperthermia has been increasingly researched and developed, espescially mechanisms relating heat induced process of nanoparticles. Studies mainly use Linear Respones Theory (LRT) to calculate Specific Loss Power (SLP). However, this theory is not always suitable in Magnetic Induction Heating (MIH). Accordingly, application of Stoner-Wohlfarth (SW) model is necessary. The first study of Hert related to thermal mechanism magnetic particles being distinguised between hysteresis loss and relaxation loss. However, this distinction was not enough to establish a full theoretical model for accurate calculation of SLP. A recent study demonstrated the effet of hysteresis to heat induction by using numerical simulation. Although the obtained results were suitable the authors have not established a full theoretical model for solving the SLP issue. Some reports showed that physical factors such as size, shape, and content effect on the SLP value. In which, the effective anisotropy constant (Keff) and size (D) of magnetic particle play the most important effect.Carrery et.al demonstrated that materials with different Keff s are consistent with theory models depending on the Keff value. Materials with high Keff is consistent with the LRT model. In constrast, materials with low Keff is consistent with the SW model Based on these theory models, the optimal SLP value is calculated by determining the optimal values of Keff and D. These values depend on characteristics of nanoparticle including content, synthesis condition and material structure. Therefore, how to select theoretical model for calculating SLP of materials is very interesting. In Vietnam, magnetic nanopartices for biomedical application are concerned by a number of research groups at Institute of Materials Science (IMS), Institute for Tropical Technology (ITT), Hanoi University of Science and Technology (HUST)... However, only research group at IMS studies deeply about physical mechanisms relating to hyperthermia. The research group not only focuses on fabircation of spinel ferrite nanoparticles (Fe3O4, MnFe2O4, CoFe2O4), manganite nanoparticles (LSMO), alloy nanoparticles (CoPt, FeCo) but also figures out physical mechanisms through experimental results and theoretical calculation. However, contribution of each physical mechanism in nanoparticles is not fully calculated . 2 Fe3O4 magnetic nanoparticle is alway the best selection for in-vitro and in-vivo magnetic hyperthermia thanks to easy fabrication and excellent biocompatibility. However, the Curie temperature (TC) of Fe3O4 (TC = 823K) is much higher than the required temperature for killing cancer cell. Thus, the saturation heating temperature is controlled by changing nanoparticle concentration and magnetic fied intensity. Recently, magnetic nanoparticles with suitable Curie temperature (TC = 42 - 46 o C), high saturation magnetisation and good biocompatibility have been focusing. The spinel- structured nanomaterial M1-xZnxFe2O4 (M= Mn, Co; 0,0 ≤x≤0.7) is high potential because of good ability in controlling TC (or saturation heating temperature). In addition, CoFe2O4 nanoparticle have attracted a great deal of attention thanks to high anisotropy constant. Therefore, this material has high SLP value. Based on the above reasons, we chose the research project for thesis, namely: Study of Magnetic Induction Heating mechanisms of spinel ferrite nanoparticles M1-xZnxFe2O4 (M=Mn, Co) Research object of the thesis: Spinel ferrite nanoparticle M1-xZnxFe2O4 (M = Mn, Co; 0,0 ≤ x ≤ 0,7). Research targets of the thesis: Fabricating spinel ferrite nanoparticle M1-xZnxFe2O4 (M = Mn, Co; 0,0 ≤x≤0,7) with controlled parameters affecting to Hc, TC and D. Establishing semi-experimental models based on experimental results to explain the correlation between SLP and (Keff, D) in order to figure out suitable mechanisms for calculating SLP value of CoFe2O4 nanoparticle Scientific and practical meaning of the thesis: Applying 2 theoritical models (LRT and SW) to figure out physical mechanisms contributing to the formation of SLP which helps to more clearly understand about MIH in order to apply magnetic nanoparticle. Research methodology: The thesis was carried out by practical experimental combining with numerical data process. Random samples were fabricated by hydrothermal and thermal decomposition synthesis. Samples were characterized by electron microscopes (FESEM and TEM). Magnetic properties of material were investigated by Vibrating- Sample Magnetometer (VSM), PPSM, SQUID. FTIR, TGA were used to evaluate the 3 presence of functional groups on magnetic nanoparticles. DLS was used to determind the hydrodynamic diameter and stability of magnetic fluid. Magnetic Induction Heating was carried out on 2 equipments: RDO-HFI- 5 kW and UHF-20A- 20 kW. Research contents of the thesis: Investigating the effect of fabrication parameters (reaction time, temperature, Zn content) on structure and magnetic properties of M1-xZnxFe2O4 nanoparticles (M = Mn, Co; 0,0 ≤ x ≤ 0,7). Investigating the effect of particle size on structure and magnetic properties of CoFe2O4 nanoparticles Investigating the correlation between D, Keff for SLP. Calculating and optimizing SLP based on particle size by numerical data process and experimental results. Using critical parameters of LRT and SW models to evaluate physical mechanisms in formation of SLP of nanoparticles with different sizes. Evaluating toxicity of magnetic fluid for hyperthermia testing on cancer cells. Layout of the thesis: The contents of thesis were presented in 5 chapters. Chapter 1 is review of spinel ferrite materials. Chapter 2 is about physical mechanisms and theoretical models applying in magnetic induction heating (MIH). Chapter 3 presents experimental methods for fabricating nanoparticles. Chapter 4 is the results of fabrication of M1-xZnxFe2O4 (M=Mn, Co; 0,0 ≤ x ≤ 0,7) obtained by hydrothermal method. Chapter 5 is the results of fabrication of CoFe2O4 obtained by thermal decomposition method. Research results of the thesis were published in 07 scientific reports including: 02 ISI reports, 03 national reports, 02 reports in national and international scientific workshop. Main results of the thesis: Investigated effect of fabrication paramters on structure and magnetic properties of M1-xZnxFe2O4 (M=Mn, Co; 0,0 ≤ x ≤ 0,7). Fabricated CoFe2O4 nanoparticles with different size. The effect of size on magnetic properties and SLP values was studied. Applying numerical data process to find out the optimal size for magnetic induction heating. Using critical parameters of LRT and SW models evaluate the mechanism contributing to formation of SLP. Evaluated toxicity of magnetic fluid, carried hyperthermia experiment on cancer cell (Sarcoma 180). 4 Chapter 1. REVIEW OF SPINEL FERRITE MATERIALS 1.1. Structure and magnetic properties of spinel ferrite materials 1.1.1. Structure of spinel ferrite materials Ferrite spinel is term of materials which have structure containing 2 crystal lattices. The interaction between 2 crystal lacttices is ferromagnetic interaction. An unit cell of spinel ferrite crytal ( lattice constant – a ≈ 8,4 nm) is formed by 32 O2- atoms and 24 cations (Fe 2+ , Zn 2+ , Co 2+ , Mn 2+ , Ni 2+ , Mg 2+ , Fe 3+ and Gd 3+ ). There are 96 positions for cations (64 octa-positions, 32 tetra-positions). 1.1.2. Magnetic property of spinel ferrite materials Based on molecular field theory, the origin of magnetic property of spinel ferrite material is the result of indirect interaction between metal ions (magnetic ions) locating in two lattices A and B through oxygen ions 1.2. Effecting factors on magnetic property of spinel ferrite nanoparticles Magnetic property of spinel ferrite nanoparticls is determined by factors including size, shape and content. 1.3 . Dynamic state of magnetic nanoparticles 1.3.1. Non-interacting magnetic nanoparticles Based on classical theory, spin- reversed speed of particle through potential energy depends on thermal energy and frequency according to Arrehenius law, calculating equation of relaxation time (τ0 ~ 10 -9 - 10 -13 s) for non-interacting magnetic nanoparticles. 1.3.2. Weakly interacting magnetic nanoparticles Shtrikmann and Wohlfarth used mean field theory to establish the expression of releaxtion time of weaky interacting magnetic nanoparticles under Vogel-Fulcher law. 1.3.3. Strong interacting magnetic nanoparticles By measuring the change of phase transition temperature by frequency in a wide range, the state of material could be determined whether spin glass or not when processing data by critical slowing down model. 1.4. Biomedical application of magnetic nanoparticle Magnetic nanoparticle has been studying for 4 medical applications including cell separation, drug delivery, MRI and magnetic hyperthermia 5 Chapter 2. PHYSICAL MECHANISMS AND THEORETICAL MODELS APPLIED IN MAGNETIC INDUCTION HEATING (MIH) 2.1. Induction heating mechanism of magnetic nanoparticls under AC magneitic field 2.1.1. Relaxation mechanism (Néel and Brown) In case of single domain size, anisotropic energy is smaller than heat energy, spin of nanoparticle could rotate every direction even without magnetic field. If roating spin while keeping particle in one direction then after a period of time, spin will return to the original position. That is Néel relaxtion time. Néel relaxation is rotation of moment of magnetic nanoparticle. Brown relaxation is the movement of magnetic nanoparticls in liquid. 2.1.2. Hysteresis loss mechanism Hysteresis loss is energy loss in a magnetism process, determined by the area of hysteresis loop of material. This process strongly depends on magnetic field intensity and intrinsic property of mangnetic nanoparticle. 2.1.3. Other mechanisms Beside 2 above mechanisms, induction heating of magnetic nanoparticle induces heat under AC magnetic field also happens by another mechanism. That is the loss induced by friction in liquid. 2.2. Theoretical models 2.2.1. Stoner-Wohlfarth (SW) model The SW model is a theoretical model use calculating the area energy of the delay of material when it magnetized to saturated. LRT model is not suitable for materials without supperparamagnetism. Accordingly, SW model is used. Theoretically, some authors calculated magnetic resistance force by following equation: [ ] (2.16) 2.2.2. LRT model LRT model describes the linear reponse of magnetic moments under magnetic field. The simulation result of magnetism process by magnetic field shows the linearity with magnetic field at  < 1. This is the condition for application of LRT model. 6 2.3. Calculation methods of Specific Loss Power (SLP) 2.3.1. Theoretical calculation of SLP For non-interacting superparamagnetic nanoparticle under AC magnetic field, maximum SLP is calculated by following equation: (2.21) 2.3.2. Experimental calculation of SLP a) Heat measurement method This is the most common method for determining heat induction capacity of magnetic liquid. SPL value is calculated by the rate of increasing temperature: (2.24) b) Hysteresis loop measurement method SLP is calculated from hysteresis loop corresponding to applied magnetic field: ∮ (2.27) 2.4. State of art of Magnetic Heat Induction study Studies of MHI used many materials such as single nanoparticle, exchange- coupled materials, core-shell materials. Supperparamagnetic nanoparticles, Fe3O4 and γ-Fe2O3, are most common studied thanks to good biocompatibility, specially success in MRI apllication. Chapter 3. EXPERIMENTAL METHODS 3.1. Fabrication of M1-xZnxFe2O4 (M = Mn, Co; 0,0 ≤ x ≤ 0,7) nanoparticle by hydrothermal method M1-xZnxFe2O4 (M = Mn, Co; 0,0 ≤ x ≤ 0,7) nanoparticles were fabricated by hydrothermal method described in the following diagram (Figure 3.1.) 7 Figure 3.1. Fabrication process of M1-xZnxFe2O4 (M = Mn, Co; 0,0 ≤ x ≤ 0,7) nanoparticles. 3.2. Fabrication of CoFe2O4@OA/OLA nanoparticles by thermal decomposition method CoFe2O4@OA/OLA nanoparticles were fabricated by thermal decomposition method described in the following diagram (Figure 3.2.) : Figure 3.2. Fabrication process of CoFe2O4 @OA/OLA nanoparticles Figure 3.2. PMAO encaosulation process. 3.2.3. Phase transition of magnetic nanoparticle from organic solvent to water Phase transition process of magnetic nanoparticle from organic solvent to water was performed in the following diagram (Figure 3.5.) 3.3. Characterization methods Samples were characterized by electron microscopes (FESEM and TEM). Magnetic properties of material were investigated by Vibrating-Sample Magnetometer (VSM), PPSM, SQUID. FTIR, TGA were used to evaluate the presence of functional groups on magnetic nanoparticles. DLS was used to determind the hydrodynamic diameter and stability of magnetic fluid. Magnetic Induction Heating was carried out on 2 equipments: RDO-HFI- 5 kW and UHF-20A- 20 kMaterial structure was studied by X-ray diffraction, electron microscopy. 8 3.4. Toxicity evaluation of magnetic fluid on cancer cell Evaluating cancer cell killing ability of magnetic fluid on cancer cell. 3.5. Magnetic hyperthermia of magnetic fluid on cancer cell Evaluating death ratio of cancer cell after magnetic hyperthermia by changing temperature and magnetic fied application time. Chapter 4. STRUCTURE, MAGNETIC PROPERTY AND MAGNETIC INDUCTION HEATING OF M1-xZnxFe2O4 (M = Mn, Co; 0,0 ≤ x ≤ 0,7) NANOPARTICLES FABRICATED BY HYDROTHERMAL METHOD 4.1. Effect of reaction temperature on structure and magnetic property 4.1.1. Effect of reaction temperature on structure Figure 4.1. X-ray diffraction of samples: MnFe2O4 (a) and CoFe2O4 (b) at different temperatures in 12 hours. Figure 4.1a and 4.1b are the X-ray diffraction of MnFe2O4 and CoFe2O4 nanoparticles fabricated by hydrothermal method at different temperatures, coded: 120 o C (MnFe1, CoFe1), 140 o C (MnFe2, CoFe2), 160 o C (MnFe3, CoFe3) and 180 o C (MnFe4, CoFe4) with reaction time of 12 hours. It was showed that both kinds of sample are single crystal expressed at characteristic peaks (220), (311), (222), (440), (442), (511), (440). When increasing temperature reaction, particle size of two kinds of sample increases. 4.1.2. Effect of reaction temperature on magnetic property Saturation magnetism Ms increases from 31,1 emu/g (MnZn1) to 66,7 emu/g (MnZn4) (Figure 4.4a) and from 59,3 emu/g (CoZn1) to 68,8 emu/g (CoZn4) when changing reaction temperature from 120 o C to 180 o C (Figure 4.4b). 25 30 35 40 45 50 55 60 65 MnFe4 MnFe3 MnFe2 MnFe1( 2 2 0 ) ( 3 1 1 ) (2 2 2 ) (4 0 0 ) (4 2 2 ) (5 1 1 ) (4 4 0 ) C - ê n g ® é ( ® .v .t .y ) 2(®é)(a) 25 30 35 40 45 50 55 60 65 (2 2 0 ) (3 1 1 ) (2 2 2 ) (4 0 0 ) (4 2 2 ) (5 1 1 ) (4 4 0 ) CoFe4 CoFe3 CoFe2 CoFe1 C - ê n g ® é ( ® .v .t .y ) 2(®é)(b) 9 Figure 4.4. Hysteresis loop of MnFe2O4 (a) và CoFe2O4 (b) nanoparticles fabricated at different temperature. Smaller figures are hysteresis loops at low magnetic field. 4.2. Effect of reaction time on structure and magnetic property 4.2.1. Effect of reaction time on structure Changing reaction time: 6h, 8h, 10h, 12h at reaction temperature 180 o C for fabrication of MnFe2O4 và CoFe2O4 nanoparticles coded: (MnFe7, CoFe7); (MnFe6, CoFe6); (MnFe5, CoFe5) và (MnFe4, CoFe4), all sample are single crystal with ferrite spinel structure. Reaction time increasing led to increasing diffraction peak intensity, decreasing peak wide which determine the decrease of particle size. 4.2.2. Effect of reaction time on magnetic property Figure 4.8. Hysteresis loops of MnFe2O4 (a) and CoFe2O4 (b) fabricated at different reaction times. Smaller figures are hysteresis loops at low magnetic field Figure 4.8 are hysteresis loops of MnFe2O4 and CoFe2O4 nanoparticles measured under mangetic field from -11 kOe to 11 kOe. In both kinds of sample, decreasing reaction time from 12h to 6h led to reduction of Ms. Magnetic resistance -80 -60 -40 -20 0 20 40 60 80 -1 10 4 -5000 0 5000 1 10 4 MnFe4 MnFe3 MnFe2 MnFe1 M ( e m u /g ) H (Oe) 0 2 4 6 8 10 -120 -90 -60 -30 0 MnFe4 MnFe3 MnFe2 MnFe1 M ( e m u /g ) H (Oe) (a) -80 -60 -40 -20 0 20 40 60 80 -1 10 4 -5000 0 5000 1 10 4 CoFe4 CoFe3 CoFe2 CoFe1 M ( e m u /g ) H (Oe) 0 10 20 30 40 -3000 -2000 -1000 0 CoFe4 CoFe3 CoFe2 CoFe1 M ( e m u /g ) H (Oe) (b) -80 -60 -40 -20 0 20 40 60 80 -1 10 4 -5000 0 5000 1 10 4 MnFe4 MnFe5 MnFe6 MnFe7 M ( e m u /g ) H (Oe) -100 -75 -50 -25 0 0 2 4 6 8 10 MnFe4 MnFe5 MnFe6 MnFe7 H (Oe) M ( e m u /g ) (a) -80 -60 -40 -20 0 20 40 60 80 -1 10 4 -5000 0 5000 1 10 4 CoFe4 CoFe5 CoFe6 CoFe7 M ( e m u /g ) H (Oe) 0 10 20 30 40 -2000-1500-1000 -500 0 CoFe4 CoFe5 CoFe6 CoFe7 M ( e m u /g ) H (Oe) (b) 10 force Hc for both kinds of samples changed but it did not follow the law of Herzer which is that Hc decreases when particle size decreases only in single domain size range. 4.3. Effect of Zn 2+ content on structure and magnetic property 4.3.1. Effect of Zn 2+ content on structure With the aim of fabricating materials possessing Curie temperature lower than 42 o C-46 o C (temperature kills cancer cell), we studied effect of Zn 2+ on structure and magnetic property of Mn1-xZnxFe2O4 và Co1-xZnxFe2O4 (x = 0,0; 0,1; 0,3; 0,5 và 0,7) nanoparticles, coded: MnZn0, MnZn1, MnZn3, MnZn5 và MnZn7; CoZn0, CoZn1, CoZn3, CoZn5 và CoZn7. All samples were fabricated at 180 o C in 12h. X-ray diffraction in figure 4.9 show that both kinds of sample are single phase spinel structure. However, diffraction peaks of Mn1-xZnxFe2O4 are sharper than that of Co1- xZnxFe2O4, meaning that the size of Mn1-xZnxFe2O4 nanoparticle is bigger than that of Co1-xZnxFe2O4 nanoparticle. In one kind of sample, increasing Zn 2+ leads to decreasing intensity of diffraction peaks showing that the particle size decreases. Figure 4.9. X-ray diffractions of Mn1-xZnxFe2O4 nanoparticles (x = 0,0; 0,1; 0,3; 0,5 and 0,7) (